Integration of biosensors on a small scale for e.g., in-home testing is increasingly being favored by healthcare providers, however it has been a challenge for years. Optical-based biosensors require bulky detection equipment and access to power supplies. Vibration sensitive biosensors (AFM, crystal-quartz balance etc.) cannot be built into a hand-held or portable device since background vibration will interfere with the signal. Biosensors made from electrical components have been considered as a good solution, however existing biosensors face several problems including limitations caused by electrostatic screening in complex media. Several methods to circumvent this problem including sample dilution and pulsed electrical properties have been explored, resulting in additional sample processing steps and the dilution of the analyte, or adding complexity to the device design. In addition, reference and calibration processes prior to use of the biosensors complicates their use.
Existing biosensors used to detect substances in bodily fluid suffer from a number of other limitations as well. For example, existing biosensors may be utilized for analyte detection; however, due to the inability to control various environmental factors surrounding the sample of bodily fluid and the biosensor, signals associated with this detection are often not accurate, not reproducible and do not provide a reliable or stable readout. Examples of existing biosensors can be found in Pedro Estrela et al., Label-Free Sub-picomolar Protein Detection with Field-Effect Transistors, Anal. Chem. 2010, 82, 3531-3536 and Eric Salm et al., Electrical Detection of Nucleic Acid Amplification Using an On-Chip Quasi-Reference Electrode and a PVC REFET; Anal. Chem. 2014, 86, 6968-6975, each of which is herein incorporated by reference.
As a result of the above limitations and restrictions, there is a need for an improved device, system and method for detecting chemical and biological substances in bodily fluid that minimizes or eliminates such limitations and restrictions.